PR_WEEK2TIMwill print on the screen the first and last day of a
specified week number (integer) or Yohkoh week ID (string). For
example:
IDL> pr_week2tim ; List current Yohkoh week
IDL> pr_week2tim,'91_46'
IDL> pr_week2tim,'91_46a' ; Last letter is optional
IDL> pr_week2tim, 4 ; Week 4 of current year
IDL> pr_week2tim, 4, year=93 ; Week 4 of 1993
Short weeks (the first or last week of the year) are flagged with an
asterisk. PR_WEEK2TIMcalls WEEKID2EX to make the conversion.